lindquist



Dec 11, 1923.

E. w. LINDQUI5T ROTARY SCREEN FOR SCREENING PULP ,AND PAPER STOCK Filed Jan. 6, 1928 m. R .1 WW N 3: mm o u\ m w \m o a 11v VENTOR.

R EST W. LINDQUIST A TfliRNEYS.

Patented Dec. 11, 1928.

UNITED STATES PATENT OFFICE.

ERNEST W. LINDQUIB T, OF HELBINGFORS, FINLAND.

ROTARY SCREEN FOB SCREENING PULP AND PAPER STOCK.

Applicatton filed January 8, 1928 Serial No. 244,812.

This'invention relates to rotary screens for screening pulp and paper stock and is more particularly directed to im rovements in the machine forming the sub cct matter of Patent No. 1,627,655 issued to me on May 10th, 1927. In that machine the apparatus embodies a plurality of screen sect ons arranged in annular series and intcriorly of each of which is formed a chamber. The inner wall of each chamber is in the format a diaphragm which is adapted through manipulation of a cam to be flcxed alternately in an inward and outward radial direction for the purpose of alternately sucking fine pulp through the screen sections and thereafter discharging such pulp through a suitable outlet duct. In the said machine, the operations ofthc diaphragms were controlled by means of a cam positioned coaxially of the chambers and located in a more or less inaccessible position, so that it was difficult to obtain access to the operating parts, and, moreover, the question of lubrication was somewhat of a problem since if i suliicient lubricant was introduced to proporly lubricate the operation of the cam, this lubricant is apt to be distributed by centrifngal force throughout the whole interior part of the a paratus with attendant diiliculties. Furtiiermore, the oil condition of the parts resulting from this act caused accumulation of dust and dirt which necessitalcd frequent cleaning.

The ob]ect of the'present invention is to overcome the disadvantage referred tow and others by so positioning the cam and the followers or shoes which cooperate with it at the front end of the machine where they will be readily accessible for repair or adjustment and to enclose these operating parts in such manner that they will not only be protected from dirt or dust but will run in oil, grease or other lubricant so that their operation will be substantially noiseless and ofiicient.

Another object of the present invention is to provide for the operation of the diaphragms from a cam through interposed leverage connections so as to minimize the ower required to operate the machine and to render such operation more smooth than heretofore. i

Another object of the invention is to more eillciently remove from the machine the screen product in order that the efiiciency and consequent protection of the machine mag be increased.

further object of this invention is to simplify the drive of the respective parts to eliminate excessive gearing with consequent economy and elimination of noise.

Features of the invention, other than those specified, will be apparent from the hereinafter detailed description and claims, when read in conjunction with the accompanfiing drawings.

T e accom anying drawings illustrate one practical em odiment of the invention, but the construction therein shown is to be understood as illustrative, only, and not as defining the limits of the invention.

Figure 1 is a longitudinal section through apparatus embodying the present invention.

igure 2 shows the apparatus of Figure 1 partly in end elevation and partly in transverse section.

Referring to the drawings, 1 designates a casing or vat which is of substantially cylindrical shape and is provided with an open to This vat may be of wood or any other suitable material and is supported in a suitable framcwork 2 mounted on an appropriate base 3.

Positioned within the vat 1 and mounted for rotation therein is a screen drum 4. This screen drum is positioned coaxially of the vat and is supported at one end by an axial trunnion 5 which is of hollow tubular section a d s mounted to rotate in a bearing 6 supported by a standard 7 secured to the base 8. The other end of the drum is in the form of an annular casting 8 which embodies a spider 9. This spider has a hub 10 mounted in abearing 11 forming a part of a standard 12 which is also mounted on the base. The drum 4 is provided with removable screen scctions 14, each covering a segmental suction chumber 15 formed between longitudinal balks or partitions 16. The inner wall of the chamber 15 is in the form of a flexible diaphragm 17 which is secured to and extends between the partitions 29. Each screen section is provided with numerous fine slots as is customary.

The jorward end of each of the suction chambers 15-is closed by the casting 8, while the after end of each chamber communicates with the chamber 18 formed between the outer end wall 19 of the drum and an inner wall 20, so that fine pulp received within the suction chambers 15 is adapted to readily exit be driven.

with minimum resistance into the chamber 18 and thence through the passage 21 formed within the hollow trunnion 5. Ashaft 22 is joui-nalled at one end at the center of the inner wall in a bearing 23 and extends forwardly through the apparatus and through the hollow trunnion or hub 10 of the spider 9 and is provided at its forward end with a pulley 24 by which this 'shaft'may Fixed to the shaft- 22 between the'pulley 24 and the bearingll is a sprockct wheel 25 connected by a chain 26 to a sprocket wheel 27. This latter sprocket wheel is fixed toa shaft 28 which extends the full length of the apparatus and carries a sprocket wheel 29 at its opposite end. This latter' sprocket wheel is connected b a sprocket chain to a sprocket wheel 30 ed on, the hollow trunnion 5 of the drum so that when the apparatus is driven by a belt cooperating with the pulley 24, both the shaft 22 and the drum will bedriveh.

It will be noted, however,' that the driving connections are so constituted as to drive the shaft 22 at a greater speed than the drum 5. Fixed on the shaft 22 at the forward end of the machine and contiguous to the .forward edge of the drum is a cam 31 adjacent the opposite faces of which are mounted; 1

plates 32 and 33. These. plates have hubs which loosely embrace the shaft 22, so that the shaft 22 may rotate within the hubs of the plates 32 and 33 and "at a greater speed than the speed of rotation of these plates. The plates are of disk form and are flanged at their outer peripheries and .a cylindrical band or sleeve .34 of rubberor other suitable flexible material is deinountably attached to these flanges so as to. form with the plates 32 and 33 a closed cylindrical chamber in which the cam-31 is housed.

Positioned interiorly of the sleeve 34 are as man shoes as there are screen sections. These s 0% 35 are juxtaposed with the respective sections and are ada' ted'to act as followers with respect 'to t e cam 31. Positioned exteriorly of the rubber sleeve and in juxtaposition with each shoe 35 is an at taching plate 36 which is secured to its corresponding shoe by means'of screws "extending through the plate 36 and through the rubber .sleeve and threaded into the shoe so as to mount both the shoe and attaching the plate on the rubber sleeve. Each attaching plate has a ball joint connection 37 with the power arm of a lever 38. All of the leversextend longitudinally through t e drum and are fulcrumed. at 39. on the inner end wall 20, as shown in Figure 1. Intermediate the ends of each lever is pivoted a link 40 arid this link is secured to a plate' 41 attached to the diaphragm 17 of the cor responding suction chambeip The end frame or casting 8 is/provided with outwardly ex tendin lugs 43, one of which is; hxtapdsed with tie free end of each levgr 38 and a spring '42 is inter osed between the end of each lever and t e corresponding lug 43. These springs are of the compression type and serve to force the free ends of the levers in an inward radial direction for the purpose of maintaining the shoes 35 in engagement with the cam 31.

With this arrangement, the cam and its shoes are housed within a'liquid tight casing which is adapted to be filled with lubricant through a suitable inlet 44 in order that these parts may run in grease in order to minimize friction and'oonsequent wear and render the operation of the machines practically noiseless.

Mounted on the upper: portion of the tank is an overflow box 45 into'which the pulp to bescreened is-fed throu h an inlet 46 while the residue is fed out irough a pipe 47. A spray pipe 48 is arranged to clean the screen sections as they rotate into the uppermost positions.'- -The dirt, slivers and some stock flow over the edge of the tank into the overflow box andv out through the outlet 47 in the usual manner.

The 1 lower 7 portion of the tank is g rovided with a cleaning openin 49 adapte to be normally closed b the sli e valve 50 which may be manually operated. froth time to time to clean out the tank. p

' The operation of the apparatus is as follows. Assumin that pulp is being intro duced through t e pipe 46 into the overflow box, this pulp will fill the tank exteriorly of the drum 14. If the apparatusis now started by rotating the pulley 24 throu h suitable driving connections, the drum wil be rotated at a fairly slow speed while the cam will be operated at a. somewhat higher speed by vir-' 'tue of theconnectioiis described and both of these parts willrotate in the same direction.

pulp will be drawn through the slots in the screen sections into the chambers 15 and on each compression operation, the pulp which .has thusbeen drawn. in will be exhausted through the chamber 18 and through the passage 21 to a suitable draw further treatment.

01f pipe for The operation is a continuous one and is found in practice to give highly 'efiicie'nt .results. The interposition of levers between the cam following shoes and the diaphragms minimize the power required for the operation of the machine and the relatively simple 1 driving connections which I have shown no verage connections parts work smoother and dust, dirt or eatraneous matter is excluded from the Wdrhmg parts so that wear is minimized. The

draw oli of the screen material through the hollow trunnion 21 and through the relatively large chamber 18 increases the output of the machine since there is practically no back pressure or obstructions to the outlet of such screen material and there is no tendency therefore for the material drawn into the suction chambers to exit through the screen when the diaphragms are flexed in an outward radial direction. p

.I wish to call especial attention to the fact that the cam,its shoes and other operating connections at the work arm ends of the levers are positioned at the front end of the machine where they are of convenient access. It is not necessary with the machine of this invention, therefore, to reach into the interior of the drum to adjust, repair or replace any of these parts. A workman can' stand extcriorly of the machine and all of these working parts are directly in front of him, is of pronounced importance in the practical operation of machines of this character. The top of the tank is o en, so as to allowifcady access to the screen sections when desirediu The foregoing detailed description sets forth the invention in its preferred practical ,7 form, but the invention is to be understood 'as fully commensurate with the appended claims.

Having thus fully described the invention, what I claim as new and desire to secure by Letters Patent is: v

1. In an apparatus of the character described, 11 screen drum circumfercntially divided to form a series of circumferentially positioned suction chambers, each of which is provided with a diaphragm adapted to be flexed to produce suction in said chambers, a cam mounted coaxily of the drum, n plurality of shoes enga ing with said cam, le-

etwcen each shoe and one of the diaphragms, and means for producing relative rotation between the drum and the cam for the purpose of operating the diaphragm through the shoe and leverage connections.

2. In an apparatus of the character described, a rotary pulp screen divided into sections and each section forming the outer wall of a chamber, flexible diaphragms each closing a chamber corresponding to a screen section, and means for operating said dia phragms, isaid means comprising a cam mounted coaxiaily of the rotary pulp screen and at one end thereof, shoes cooperating with said cam, and leverage connections between the shoes and the respective diaphragms.

3. in an apparatus of the character described, a screen drum circumferentially divided to form a series of circumfercntiallv positioned suction chambers, each of which is provided with a diaphragm adapted tobe flexed to produce suction in said chambers, a cam mounted coaxially of the drum, a

plurality of shoes engaging with said cam,

ievcrage connections between each shoe and one of the diaphragms, and means for producing relative rotation between the drum and the cam for the urpose of operating' the diaphragm through the shoe and leverage connections, and a closed casing enclosing and housing the shoes and the cam and adapted to contain a lubricant whereby the shoes and cam will operate within a lubricant bath.

4. In an apparatus of the character described. a rotary pulp screen cylinder provided interiorly with suction chambers, one

wall of each of which embodies a diaphragm,

a cam mounted to rotate coaxially of the cylinder, a plurality of shoes bearing on the cam, and each of which is operatively con nected to one of the diaphragms, and a casing enclosing and housing all of the shoes and the cams and adapted to contain a lubricant whereby the shoes and cam will opcrate in a bath of lubricant. 1

5. In an apparatus of the character described, a rotary pulp screen cylinder provided interiorly with suction chambers, one wall of each of which embodies a diaphragm, a cam mounted to rotate .coaxially of the cylinder, a plurality of shoes bearing on the cam, a lever secured to each shoe, and also secured to one of the diaphragms and each of said levers being fulcrumcd to rotate with the cylinder, and springs for maintaining the shoes in engagement with the cam,

6. In an apparatus of the character do; scribed, a rotary pulp screcn'cylinder provided interiorly with suction chambers, one wall of each of which embodies 11 diaphragm, a cam mounted to rotate coaxially of the cylinder, a plurality of shoes bearing on the cam, a lever secured to each shoe, and also secured to one of the diaphragms and each of said levers being fulcrumed to rotate with the cylinder, springs for maintaining the shoes in engagement with the cam, and a liquid tight housing enclosing the shoes aid the cam and adapted to contain a lubricant whereby the cam and shoes may operate in a lubricant bath. I

7. In an apparatus of the character described, a screen drum embodying an annular series of suction chambers, the outer circumferential wall of each of which is perdiaphragms, and means for im arting rotary -movement to the drum an cam with the eam-movin at a higher speed than the cylinder, where y the diaphragms are operated through the shoe and lever connections.

8. In an apparatus of the character described, a screen drum embodying an annular series of suction chambers, the outer circumerential' wall of each-of which is perforated and the inner circumferential wall of-each of which embodies a diaphragm, a cam positioned coaxially of and within the drum and adjacent one end thereof, a plurality of shoes bearing against the cam, a series of levers, one end of each of which is fulcrumed on the drum and which levers ex: tend longitudinally of the drum and are secured at their opposite ends to the shoes, means for securing each lever to one of the diaphragms, means for imparting rotary movement to the drum and cam with the cam moving ata higher speed than the cylinder, whereby, the diaphragms are operated through the shoe and lever connections, and

a liquid tight casing enclosing the cam and the shoes and adapted to contain lubricant.

' 9. In an apparatus of the character dc-.

scribed, a screen drum embodying an {innular series of suction chambers, the outer cir- ,cumferential wall of each of which is perdrum and adjacent one end thereof, a plat-=4 ality of shoes bearing against the cam," a series of levers, one end of each of which is fulcrumed'on the drum and which levers extend longitudinally of the drum and are secured at their opposite ends to the shoes, means for securing eachlever to one of the diaphragms, -means for imparting rotary movement to the'drum and cam with 'the cam moving, at a higher speed than the cylinder, whereby the diaphragm; are operated through the shoe and lever connections, and a liqiiid tight casing enclosing the -cam and the shoes and adapted to contain lubricant, the wall of the liquid tightcasing being flexible to permit operation of the shoes bv the cam.

In testimony whereof I havesigned the foregoing specification.

ERNEST W. LINDQUIST. 

